Today, Facebook rolled out what's arguably one of the most complicated product updates it's made in its short history, a series of new features and revamps to existing ones that aren't directly connected to one another, but which have a central aim: making Facebook a flexible and universal communications hub.

"What we're trying to do here is build a social platform. That's very different from building a social application," Facebook founder and CEO Mark Zuckerberg said in the press conference. "The difference between building a social application and building a social platform is when you're building an application you're building it for one use case." A platform, meanwhile, can handle anything.

So here's what the company announced.

New Groups

Facebook members have been able to partake in "groups" for years now, but this revamp makes them significantly more feature-heavy--and more intimate. They're designed to be used by family members, sports teams, school classes, and the like, not for en masse followings of causes or political rallies. For those, Facebook encourages members to use Events or Fan Pages.

First of all, you can't just arbitrarily join a group--another member has to invite you. Membership is limited to 250 people at this point. New features include collaborative documents, photo and video sharing, and the ability to invite all members of a group to an event. There's also live group chat, something that raises the uneasy specter of Google Wave, a product that also aimed to revolutionize intimate group communication and collaboration but ultimately was a complete flop. Groups can have e-mail addresses assigned to them too, which Facebook says can only be e-mailed by e-mail addresses that match up to Facebook accounts that are in the group.

This format--invite-only, and can only be invited by confirmed Facebook friends, but sometimes completely public otherwise--is a fairly new philosophy for the mainstream Web. It'll be interesting to see how this catches on and what social dynamics and problems result.

"Old" Facebook groups still exist and have not been converted to "new" ones. There is, as of yet, no way to convert an old group to a new one.

"Download My Information"

This permits Facebook members to download into a ZIP file a complete archive of everything that they have uploaded to Facebook: profile data, photos and videos, wall posts, notes, comments, friend lists, etc. This file is then kept on the member's hard drive but can only be accessed through a strict system of passwords, e-mail address verification, and even Captchas.

My best guess is that "Download Your Information" is a bit of an olive branch to the data-portability community, which has been clamoring for Facebook to make it possible to port profile information off its servers--and of which David Recordon, the Facebook product manager who demonstrated the feature, was a vocal member long before Facebook hired him. As a feature, it's pretty limited, though the security controls around it seem to be legitimately robust.

For example, the file does not contain friends' contact information, one of the few things that would seem highly useful beyond simply archival purposes--you could, presumably, use this to populate an address book or spreadsheet of contacts. Facebook also hasn't been totally clear about the file formats contained within the ZIP file and how far back the information goes. (We've pinged them for comment.)

Still, especially since Facebook now allows members to upload high-resolution photos thanks to an overhaul of its Facebook Photos product, this will likely mean that more members are using the service for a sort of basic media storage.

Third-party application dashboard

Perhaps partially in response to privacy advocates who say that Facebook isn't clear enough with how much of members' personal information is shared when they opt into the millions of third-party sites using the Connect log-in product or building directly on Facebook's developer platform, the company now has a "dashboard" for managing which applications you're connected to and which data permissions have been granted to them. There's also a log of what data has been accessed by each application.

Facebook says that it hopes this will not only be helpful for users but that it will also increase accountability on behalf of developers and app manufacturers.